Preparation of sulfonated lubricating agents for leather and furs

ABSTRACT

This invention relates to sulfonated lubricating agents for leather and furs. More specifically, this invention relates to a process for the production of sulfonated lubricating agent for leather and tanned furs consisting of the steps of: 
     (a) sulfochlorinating higher fatty acids or esters of higher fatty acids having chain lengths of from 8 to 24 carbon atoms with chlorine and SO 2  at a temperature of from about 20° to 90° C. under UV-radiation for a time sufficient to obtain a compound having a chlorine content of from about 5 to 30 percent by weight and a content of --SO 2  Cl groups of from about 1 to 20 percent by weight, the ratio of chlorine atoms to --SO 2  Cl groups being from about 0.7:1 to 70:1; and 
     (b) forming a water-emulsifiable alkali metal, ammonium, or lower alkyl-ammonium salt of the compound produced in step (a).

This application is a continuation of co-pending U.S. patent applicationSer. No. 259,526, filed May 1, 1981, now abandoned.

FIELD OF THE INVENTION

This invention relates to sulfonated lubricating agents for leather andfurs. More specifically, this invention relates of leathers and peltsthat can be obtained in a substantially single-step reaction.

BACKGROUND OF THE INVENTION

In general, water-emulsifiable leather and fur fatting agents andlubricants are produced by sulfating unsaturated natural or syntheticfats, oils, or waxes with the usual sulfating agents, such as commercialsulfuric acid or oleum. As a rule, sulfation is continued only untilsufficient emulsifiability is attained and the sulfation productsobtained still have a considerable iodine number. However, theunsaturated character of these products unfavorably influences theiroxidation stability and, hence, the shelf life of the lubricants as wellas the light resistance of the leather and furs lubricated with them.Furthermore, the sulfuric acid esters formed by sulfation have littleresistance to acid action in the leather and readily become saponified,thereby making it possible for free fatty acids to form and, ifsaturated fatty acids are present in sufficient quantity, fatty acidexudation to develop.

This drawback is eliminated, according to U.S. Pat. No. 3,370,005, byreducing the number of double bonds by 20 to 70 percent by partialchlorination of the unsaturated raw materials. The subsequent sulfationyields lubricants with improved properties regarding light resistanceand shelf life, but even these products are sensitive to acid and notentirely stable in storage.

Leather lubricants are known from both U.S. Pat. No. 3,300,525 andFrench patent No. 2,031,167 which are obtained from sulfonation and,possibly partial chlorination of unsaturated natural or synthetic fattyacid esters. Sulfur trioxide, mixed with inert gases, if applicable, isused as the sulfonating agent. Due to their content of genuinesulfonates, such sulfonation products are acid-resistant. However, theyretain a partially unsaturated character so that a degree of oxidationsensitivity and light sensitivity remains. Also, the sulfonation ofunsaturated substances with sulfur trioxide is difficult because of theoccurring strong oxidation reaction which makes it hard to prevent darkdiscolorations and undesired polymerizations. Not even a subsequenttreatment of such sulfonates by means of the usual bleaching agents caneliminate the above disadvantages.

U.S. Pat. No. 3,988,247, incorporated herein by reference, disclosesfat-liquoring agents for leather or furs based upon sulfonatedchlorination products of natural or synthetic higher fatty acids oresters of fatty acids in the form of their alkali metal, ammonium, oramine salts. These agents consist of those sulfonated chlorinationproducts that were obtained by chlorinating higher fatty acids or ofesters of higher fatty acids having chain lengths of from 8 to 24 carbonatoms up to a chlorine content of from about 20 to 45 percent by weight,the products of chlorination generally not containing any olefinicdouble bonds, and subsequently sulfonating said products with SO₃ toattain an SO₃ content of from 40 to 150 mol, based on the products ofchlorination.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an improved procedure forpreparing fat-liquoring agents for leathers or furs.

It is also an object of the invention to provide a substantiallysingle-step reaction capable of producing effective sulfonatedchlorination products for the fat-liquoring of leathers and furs.

It is a further object of the invention to provide a process for theproduction of a sulfonated lubricating agent for leather and tanned furscomprising sulfochlorinating higher fatty acids or esters of higherfatty acids having chain lengths of from 8 to 24 carbon atoms withchlorine and SO₂ at a temperature of from about 20° to 90° C. underUV-radiation for a time sufficient to attain a chlorine content of fromabout 5 to 30 percent by weight and a content of SO₂ Cl groups of fromabout 1 to 20 percent by weight, the ratio of chlorine atoms to SO₂ Clgroups being from about 0.7:1 to 70:1, followed by saponification.

These and other objects of the invention will become more apparent fromthe discussion below.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that effective sulfonated chlorination productsfor the liquoring of leather and tanned furs can be obtained in the formof their alkali metal, ammonium, or amine salts in a single stepreaction where natural or synthetic higher fatty acids or esters offatty acids are subjected to sulfochlorination with chlorine and sulfurdioxide. The basic reaction comprises sulfochlorinating higher fattyacids or esters of higher fatty acids having chain lengths of from 8 to24 carbon atoms with chlorine and SO₂ at a temperature of from about 20°to 90° C. under UV-radiation for a time sufficient to attain a chlorinecontent of from about 5 to 30 percent by weight and a content of SO₂ Clgroups of from about 1 to 20 percent by weight, the ratio of chlorineatoms to SO₂ Cl groups being from about 0.7:1 to 70:1, which reaction isfollowed by saponification.

Until now, it was believed that the sulfochlorination reaction can besuccessfully applied only to paraffins and cycloparaffins (RomppsChemie-Lexikon, 7th edition, pages 3398 and 3399). In contrast, thesulfochlorination of all products containing oxygen should proceedunfavorably (Lindner, Tenside, Textilhilfsmittel, Waschrohstoffe, Vol.I, p. 714, 1964). Consequently it is very surprising that theapplication of the sulfochlorination process to higher fatty acids oresters of higher fatty acids under the conditions described herein leadsto effective fat-liquoring agents for leather and tanned furs whoseeffectiveness even surpasses that of the products of U.S. Pat. No.3,988,247.

To produce the lubricants of the invention, it is preferred to startwith naturally occurring higher fatty acids or esters of higher fattyacids having from 8 to 24, preferably 10 to 20, carbon atoms. Mixturesof fatty acids or fats or oils as present in naturally occurringaliphatic substances, especially those with a share of singly orrepeatedly unsaturated fatty acids, are preferred. Preferably thestarting material is a fatty acid compound selected from the groupconsisting of higher fatty acids having from 8 to 24 carbon atoms,esters of said higher fatty acids with alchohols selected from the groupconsisting of alkanols having 1 to 24 carbon atoms, alkanediols having 2to 6 carbon atoms, alkanetriols having 3 to 6 carbon atoms,alkanetetraolso having from 4 to 6 carbon atoms and alkanehexaols having6 carbon atoms, and naturally occurring fats, oils and waxes containingfatty acids having 8 to 24 carbon atoms. Examples of such fatty acidcompounds are coconut oil, soybean oil, palm kernel oil, cottonseed oil,rapeseed oil, linseed oil, castor oil, sunflowerseed oil, olive oil,neat's foot oil, peanut oil, herring oil, cod liver oil, shark liveroil, whale oil, tallow fat or lard, furthermore the fatty acid mixtureobtained from these fats or oils, and the naturally occurring wax esterssuch as sperm oil. Also, even aliphatic fatty acid compounds containingno unsaturated fatty acids or with a reduced content of unsaturatedfatty acids, such as the saturated fats obtained by pressing,crystallization, or distillation, or partially or completely hardenedfats or oils, can be utilized as starting materials.

Additionally suitable raw materials for the manufacture of lubricantsaccording to the invention include synthetically produced esters ofsaturated or unsaturated fatty acids having from 8 to 24, preferably 10to 20, carbon atoms, such as decanecarboxylic acid, palmitic acid,stearic acid, behenic acid, dodecenecarboxylic acid, oleic acid,linoleic acid or alkanoic acids produced by paraffin oxidation, withmono- or polyhydric aliphatic alcohols having from 1 to 6 carbon atoms,such as methanol, ethanol, isopropanol, butanol, ethyleneglycol,1,2-propyleneglycol, glycerin, pentaerythrite or sorbitol, or higheralcohols having 8 to 24 carbon atoms, such as decylalcohol oroleylalcohol.

Due to their ready availability the natural animal or vegetable fats,oils or waxes are the products obtained from ester interchange withlower alkanols, in particular, methyl alcohol, and the correspondingfatty acid mixtures are preferred as raw materials.

The above-mentioned starting materials are sulfochlorinated by awell-known method by the simultaneous introduction of Cl₂ and SO₂ at amolar ratio of from about 85:1 to 1.4:1. The reaction temperature isfrom about 20° to 90° C. and is maintained at the desired level bycooling, if necessary A reaction temperature of from about 40° C. to 75°C. is preferred. The reaction is facilitated by radiation with UV-light(mercury vapor lamp). The reaction is complete after approximately 2 to10 hours, after which time from about 5 to 30 percent by weight ofchlorine and from about 1 to 20 percent by weight of SO₂ Cl groups havebeen added. The ratio of chlorine atoms to SO₂ Cl groups in the productof the reaction is from about 0.7:1 to 70:1, preferably from about 2:1to 20:1, more preferably from about 3:1 to 7:1.

Subsequent saponification is performed with aqueous, approximately 30percent sodium or potassium hydroxide solution at approximately 50° C.,the neutralization being carried out either with an excess of the samealkali metal hydroxides or with ammonia solution or with an aliphatic orcycloaliphatic amine or an alkanolamine having from 2 to 6 carbon atoms,such as triethanolamine. Liquid, highly concentrated products that canbe emulsified in water and have an excellent fastness to oxidation,light, and acid are obtained, which are eminently suitable for thelubrication or fat-liquoring of light-colored, pastel-tinted, and whiteleathers as well as for the fat-liquoring of valuable and delicatetanned furs.

If dark-colored or more unsaturated raw materials are used, bleachingthe sulfonation products may be recommended. This is accomplished in theusual manner by adding small quantities of approximately 0.5 to 5percent, preferably 1 to 4 percent, H₂ O₂ solutions to the acidsulfonation product at temperatures of from about 20° and 80° C.,preferably from about 40° and 60° C. Through this measure it is possibleto lighten dark-colored sulfonatin products very considerably.

The products are used in the usual manner in the form of aqueousemulsions for the fat-liquoring or leather or for the treatment of furs.Preferably the sulfonated lubricants of the invention are applied to theleather and tanned furs by treating the leather in vats at a temperatureof from about 40° to 80° C., preferably about 60° C., with a float oraqueous liquor of from about 80 to 250 percent, preferably from about100 to 120 percent, containing from about 3 to 10 percent of thesulfonated lubricants of the invention, both based on the amount of theleather or tanned furs being treated.

The products of the invention are self-emulsifying so that thesupplemental addition of emulsifiers is generally not required. However,to achieve specific effects, the sulfonation products may be combinedwith the corresponding unsulfonated chlorination products or otherconventional leather treatment agents, such as unsulfonated oils orfats, for example, fish oil, sperm oil, neat's foot oil, and the like,or synthetic lubricants such as chloroparaffins, paraffin sulfonates,sulfated natural fats or oils or synthetic fatty acid esters, or mineraloils or the like, optionally in conjunction with anionic, nonionic, orcationic emulsifiers, preferably non-ionic surface-active compounds,such as ethylene oxide addition products to higher fatty alcohols,alkylphenols or alkylamines having 10 to 20 carbon atoms in the alkyl.Stabilization of the products may be accomplished by rendering hydrogenchloride residues possibly still present or newly formed harmless bymeans of epoxy compounds in amounts from 0.5 to 5 percent by weight.Pertinent examples are: glycide, epichlorohydrin, glycidyl ethers ofmono- or polyhydric alcohols, such as glycol, glycerin, or sorbitol aswell as epoxidized fats such as epoxidized soy bean oil, linseed oil oroleic acid butylester.

The products are well absorbed by the leather and yield excellentlubricating and softening action, with a remarkable resistance to waterand aqueous or organic detergent solutions. Their tendency to migrateunder thermal stress is minimal so that fusing operations or thevulcanization of rubber soles to shoe uppers can be carried out withoutdifficulties. The good light, oxidation, and acid resistance of thesulfonated products of the invention, which also makes them suitable forthe lubrication of sensitive and light-colored leathers and furs, is tobe particularly emphasized. The treated leather or furs arecharacterized by their feeling especially pleasantly soft and oiled tothe touch and by a beautiful glossiness of the fur.

The examples below are intended to illustrate the invention and shouldnot be construed as limiting the invention thereto. Thesulfochlorination reactions described in the examples were carried outin the following manner:

A glass reactor column filled with Raschig rings and enclosed by adouble-jacket for heating and cooling liquid stood atop a 2 literround-bottom flask having a bottom drain. The starting material waspumped through the bottom drain of the flask and then through a heatablerising tube into the head of the reaction column by means of a hosepump. The gases, chlorine and sulfur dioxide, were introduced throughneedle valves at the lower end of the column. Rotameters were used forthe metering. The flow rate of the gases was from about 25 to 120liters/hr for the chlorine and from about 4 to 50 liters/hr for the SO₂.The HCl gas produced was drawn off together with the rest of theunreacted starting gases through a washing bottle system at the head ofthe reaction column. The glass reaction column was irradiated from theoutside with a mercury vapor lamp.

EXAMPLES Example 1

One kilogram of tallow fatty acid (C₁₆ -C₁₈) methyl ester was heated to45° C. in the reactor and circulated with a hose pump at a rate ofapproximately 1 liter/hr. Chlorine (40 liters/hr) and SO₂ (7 liters/hr)were introduced in a counter-current into the reactor, irradiated fromthe outside by a mercury vapor lamp. The reaction, which wasspontaneous, was evidenced by the formation of HCl vapor.

The reaction was complete after 220 minutes, and the reaction product(1350 gm) was freed of the dissolved gases (mainly HCl) under vacuum.The product contained 17 percent by weight of organically bound chlorineand 7.7 percent by weight of SO₂ Cl groups.

The saponification and neutralization was carried out with 300 gm ofaqueous 30 percent NaOH at temperatures of from 40° to 50° C. The resultwas a stable emulsion that contained approximately 40 percent methylester sulfonate of chlorinated tallow fatty acid, 42 percent chlorinatedtallow fatty acid methyl ester, and 18 percent inorganic salts andwater.

Example 2

One kilogram of coconut oil fatty acid (C₁₂ -C₁₈) methyl ester wasreacted with 455 gm of chlorine (41.5 liters/hr) and 90 gm of SO₂ (9liters/hr) within 3.5 hours at 40° C. under UV-irradiation. Afterremoval of the dissolved gases, particularly HCl, under vacuum, 1319 gmof sulfochlorination product with a content of 14.4 percent by weight ofchlorine and 8.5 percent by weight of SO₂ Cl were obtained.

An amount of 1.151 gm of the reaction product was saponified andneutralized with 268 gm of a 31 percent solution of sodium hydroxide.The homogenized product contained approximately 50 percent by weight ofchlorosulfonated coconut oil fatty acid methyl ester, 30 percent byweight of chlorinated coconut oil fatty acid methyl ester, and 20percent by weight of inorganic salts and water. The product formed astable emulsion when diluted with water.

Example 3

One kilogram of palm kernel oil was treated with 410 gm of chlorine (26liters/hr) and 123 gm of SO₂ (8.6 liters/hr) at 50° C. over 5 hoursunder UV-irradiation in the apparatus described. The product obtainedwas freed from gas under vacuum. The yield was 1340 gm ofsulfochlorination product with a content of 13.4 percent by weight ofchlorine and 10.5 percent by weight of SO₂ Cl.

An amount of 1166 gm of the reaction product was saponified andneutralized with 421 gm of a 31 percent aqueous solution of sodiumhydroxide at 50° C. The result was a stable emulsion with 30 percent byweight of chlorinated palm kernel oil and 28 percent by weight ofinorganic salts and water.

Example 4

One kilogram of fancy tallow (C₁₆ -C₁₈) was reacted in the sameapparatus with 440 gm of chlorine (25.5 liters/hr) and 130 gm of SO₂(8.5 liters/hr) at 50° C. over 5.5 hours and under VU-irradiation. Afterthe removal of the gases, 1322 gm of the sulfochlorination product witha content of 15.4 percent by weight of chlorine and 9.7 percent byweight of SO₂ Cl were obtained.

Nine hundred and eighty grams of this product were hydrolyzed andneutrialized at 50° C. with 261 gm of a 31 percent of sodium hydroxide.The resulting emulsion was stable and contained approximately 47 percentby weight of chlorosulfonated tallow, 31 percent by weight ofchlorinated tallow, and 22 percent by weight of inorganic salts andwater.

Example 5

Leather for uppers after-tanned with synthetic or vegetable or resintanning agents, or with a combination of the mentioned tanning agents,was fat-liquored for 45 minutes at 60° C. in a vat with from 100 to 120percent of bath solution and from 5 to 6 percent of thesulfochlorination product according to Example 2 as fat-liquoringsubstance, based upon the weight of the leather. The leathers, whichwere dried and finished by the conventional method, were characterizedby a soft, supple, and full feel, good grain stability, as well asexcellent fastness to light and oxidation.

Example 6

Chrome-tanned and dyed garment leather was fat-liquored in the vat for45 minutes at 60° C. with from 100 to 120 percent of bath solution, from7 to 10 percent of fat-liquoring substance consisting of a mixture of 80percent by weight of the sulfochlorination product according to Example1 and 20 percent by weight of a corresponding nonsulfonated butchlorinated tallow fatty acid methyl ester. The leathers, which weredried and finished by the conventional method, were characterized by asoft, supple, and full feel, as well as by excellent fastness to lightand oxidation.

Example 7

Pastel-colored, chrome-tanned glove leather of lambs' skins wereliquored in the vat for 45 minutes at 60° C. with 100 percent of bathsolution and from 6 to 8 percent of fat-liquoring substance consistingof a mixture of 75 percent by weight of the sulfochlorination productaccording to Example 3, 21 percent by weight of chlorinated tallow fattyacid methyl ester that was not sulfonated, and 4 percent by weight oftallow fatty acid amine reacted with 4 mols of ethylene oxide, and thendried and finished by the conventional method. The leathers werecharacterized by an elastic, supple, soft feel and good light-fastness.

Example 8

Smoother neat's leather pickled in the usual manner was tanned with 8percent of a commercial chrome-tanning agent with a content of 25percent of Cr₂ O₃ and 100 percent of bath solution and then pre-liquoredin the same bath solution with 2 percent of fat-liquoring substanceconsisting of a mixture of 95 percent by weight of the sulfochlorinationproduct according to Example 4, and 5 percent by weight of tallow fattyalcohol reacted with 20 mols of ethylene oxide. The upholstery leatherthat was tanned a second time by the usual method, dyed, andfat-liquored a second time with from 8 to 10 percent of thesulfochlorination product and then dried, was distinguished by a supple,soft feel and good light fastness.

The preceding specific embodiments are illustrative of the practice ofthe invention. It is to be understood, however, that other expedientsknown to those skilled in the art or disclosed herein, may be employedwithout departing from the spirit of the invention or the scope of theappended claims.

We claim:
 1. A process for the production of sulfonated lubricatingagent for leather and tanned furs consisting of the steps of:(a)simultaneously sulfochlorinating esters of higher fatty acids havingchain lengths of from 8 to 24 carbon atoms with chlorine and SO₂, themolar ratio of chlorine to SO₂ being from about 85:1 to 3:1, at atemperature of from about 40° to 75° C. under UV-radiation for a timesufficient to obtain a compound having a chlorine content of from about5 to 30 percent by weight and a content of --SO₂ Cl groups of from about1 to 20 percent by weight, the ratio of chlorine atoms to --SO₂ Clgroups being from about 2:1 to 20:1; and (b) forming awater-emulsifiable alkali metal, ammonium, or lower alkyl-ammonium saltof the compound produced in step (a).
 2. The process of claim 1, whereinthe esters comprise naturally occurring mixtures of higher fatty acidshaving chain lengths of from 8 to 24 carbon atoms esterified withalcohols selected from the group consisting of alkanols having from 1 to24 carbon atoms, alkanetriols having from 3 to 6 carbon atoms,alkanetetraols having from 4 to 6 carbon atoms, and alkanehexaols having6 carbon atoms.
 3. The process of claim 2, wherein the esters are methylesters of fatty acids having chain lengths of from 10 to 20 carbonatoms.
 4. The process of claim 1, wherein the ratio of chlorine atoms to--SO₂ Cl groups is from about 3:1 to 7:1.
 5. A process for theproduction of sulfonated lubricating agent for leather and tanned fursconsisting of the steps of:(a) simultaneously sulfochlorinating estersof fatty acids comprising naturally occurring mixtures of higher fattyacids having chain lengths of from 8 to 24 carbon atoms esterified withalcohols selected from the group consisting of alkanols having from 1 to24 carbon atoms, alkanetriols having from 3 to 6 carbon atoms,alkanetetraols having from 4 to 6 carbon atoms, and alkanehexaols having6 carbon atoms with chlorine and SO₂, the molar ratio of chlorine to SO₂being from about 85:1 to 3:1, at a temperature of from about 40° to 75°C. under UV-radiation for a time sufficient to obtain a compound havinga chlorine content of from 5 to 30 percent by weight and a content of--SO₂ Cl groups of from about 1 to 20 percent by weight, the ratio ofchlorine atoms to --SO₃ Cl groups being from about 2:1 to 20:1; and (b)forming a water-emulsifiable alkali metal, ammonium, or loweralkyl-ammonium salt of the compound produced in step (a).